No Gimli rules? How about drink whenever Gimli shows his heart of gold and/or is funny/comedic relief.
Also when Gollum says "gollum".
Also when evil things other than orcs and uruk-hai dies, like trolls, leaders, olifants, nazgul.

For the beer drinkers out there, there is not enough rules, considering the movies are 3 hours long and the point is to get drunk.

A few friends and I brought beers to the premier of The Hobbit and played a drinking game with different rules.I did not know the movie was gonna be as long as it was so I missed like half of it because i kept having to get up to go pee.